From: Alok Rathore <alok.rathore@samsung.com>
To: wangyang.guo@intel.com
Cc: akpm@linux-foundation.org, axboe@fb.com, dan.liang@intel.com,
hch@lst.de, kbusch@kernel.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
ming.lei@redhat.com, rrendec@redhat.com, sagi@grimberg.me,
tglx@linutronix.de, tianyou.li@intel.com,
tim.c.chen@linux.intel.com,
virtualization@lists.linux-foundation.org,
asml.silence@gmail.com, cpgs@samsung.com, gost.dev@samsung.com,
alokrathore20@gmail.com, nitheshshetty@gmail.com,
Alok Rathore <alok.rathore@samsung.com>
Subject: Re: [PATCH v2] lib/group_cpus: make group CPU cluster aware
Date: Tue, 28 Jul 2026 20:23:03 +0530 [thread overview]
Message-ID: <561480862.11785314102640.JavaMail.epsvc@epcpadp1new> (raw)
In-Reply-To: <20260113022958.3379650-1-wangyang.guo@intel.com>
For higher number of jobs(>=64), we are seeing ~8% regression with this patch.
Tool: fio with io_uring engine [1]
+------------+------------+-------------------+
| numjobs | before | after patch |
+------------+------------+-------------------+
| 1 | 89 | 88.8 (-0.22%) |
| 2 | 169 | 168 (-0.59%) |
| 4 | 338 | 337 (-0.30%) |
| 8 | 533 | 533 (0.00%) |
| 16 | 538 | 541 (+0.56%) |
| 32 | 685 | 716 (+4.53%) |
| 64 | 933 | 859 (-7.93%) |
| 128 | 941 | 867 (-7.86%) |
+------------+------------+-------------------+
* Metric: IOPS (K) (Block device, QD = 1, bs = 4K, Random Read)
As shown in the table above, while performance is comparable at low job
counts, there is a drop starting from 64 jobs after this patch.
HW info:
Intel(R) Core(TM) Ultra 7 265K
CPU=20
IRQ-CPU are 1:1 mapped.
[1] fio -filename=/dev/nvme0n1 -direct=1 -size=4g -rw=randread \
-numjobs=$(numjobs) -bs=4096 -ioengine=io_uring -iodepth=1 \
-name=uring_test --registerfiles=1 --ramp_time=5 \
--group_reporting --thread
next prev parent reply other threads:[~2026-07-29 8:35 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20260728145333epcas5p427c6b6d72bff02de3f29e6a6a2108958@epcas5p4.samsung.com>
2026-01-13 2:29 ` [PATCH v2] lib/group_cpus: make group CPU cluster aware Wangyang Guo
2026-07-28 14:53 ` Alok Rathore [this message]
2026-07-30 6:58 ` Guo, Wangyang
2026-08-04 13:05 ` Nitesh Shetty
2026-08-05 7:50 ` Guo, Wangyang
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